From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: "Sérgio Peixoto" <sergio.peixoto@gmail.com>,
"Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>,
"Brandon Williams" <bwilliams.eng@gmail.com>,
git@vger.kernel.org
Subject: Re: [PATCH] attr: do not mark queried macros as unset
Date: Tue, 22 Jan 2019 13:48:10 -0800 [thread overview]
Message-ID: <xmqqlg3ce545.fsf@gitster-ct.c.googlers.com> (raw)
In-Reply-To: <20190118213458.GB28808@sigill.intra.peff.net> (Jeff King's message of "Fri, 18 Jan 2019 16:34:58 -0500")
Jeff King <peff@peff.net> writes:
> On Fri, Jan 18, 2019 at 11:58:01AM -0500, Jeff King wrote:
>
>> Now, on to the actual bug. The simplest reproduction is:
>>
>> (echo "[attr]foo bar"; echo "* foo") >.gitattributes
>> git check-attr foo file
>
> Actually, even simpler is to just "binary", which is pre-defined as a
> macro. :)
>
>> which should report "foo" as set. This bisects to 60a12722ac (attr:
>> remove maybe-real, maybe-macro from git_attr, 2017-01-27), and it seems
>> like an unintentional regression there. I haven't yet poked into that
>> commit to see what the fix will look like.
>
> So here's the fix I came up with. +cc Duy, as this is really tangled
> with his older 06a604e670.
>
> -- >8 --
> Subject: [PATCH] attr: do not mark queried macros as unset
>
> Since 60a12722ac (attr: remove maybe-real, maybe-macro from git_attr,
> 2017-01-27), we will always mark an attribute macro (e.g., "binary")
> that is specifically queried for as "unspecified", even though listing
> _all_ attributes would display it at set. E.g.:
>
> $ echo "* binary" >.gitattributes
>
> $ git check-attr -a file
> file: binary: set
> file: diff: unset
> file: merge: unset
> file: text: unset
>
> $ git check-attr binary file
> file: binary: unspecified
>
> The problem stems from an incorrect conversion of the optimization from
> 06a604e670 (attr: avoid heavy work when we know the specified attr is
> not defined, 2014-12-28). There we tried in collect_some_attrs() to
> avoid even looking at the attr_stack when the user has asked for "foo"
> and we know that "foo" did not ever appear in any .gitattributes file.
>
> It used a flag "maybe_real" in each attribute struct, where "real" meant
> that the attribute appeared in an actual file (we have to make this
> distinction because we also create an attribute struct for any names
> that are being queried). But as explained in that commit message, the
> meaning of "real" was tangled with some special cases around macros.
>
> When 06a604e670 later refactored the macro code, it dropped maybe_real
I think 60a12722ac is what you meant here.
> entirely. This missed the fact that "maybe_real" could be unset for two
> reasons: because of a macro, or because it was never found during
> parsing. This had two results:
>
> - the optimization in collect_some_attrs() ceased doing anything
> meaningful, since it no longer kept track of "was it found during
> parsing"
>
> - worse, it actually kicked in when the caller _did_ ask about a macro
> by name, causing us to mark it as unspecified
next prev parent reply other threads:[~2019-01-22 21:48 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-17 15:47 Change on check-attr behavior Sérgio Peixoto
2019-01-17 16:07 ` Jeff King
2019-01-18 9:41 ` Sérgio Peixoto
2019-01-18 16:58 ` Jeff King
2019-01-18 21:34 ` [PATCH] attr: do not mark queried macros as unset Jeff King
2019-01-18 21:46 ` Jeff King
2019-01-18 22:19 ` Stefan Beller
2019-01-22 7:19 ` Jeff King
2019-01-22 9:50 ` Duy Nguyen
2019-01-22 22:00 ` Junio C Hamano
2019-01-21 10:05 ` Duy Nguyen
2019-01-22 7:21 ` Jeff King
2019-01-22 9:34 ` Duy Nguyen
2019-01-22 21:48 ` Junio C Hamano [this message]
2019-01-23 5:40 ` Jeff King
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